This invention relates to electrical connection arrangements having a housing into which a cable can be received and one or more insulation-piercing electrical contacts are mounted to displace the cable insulation and establish electrical contact with a cable conductor and to a method for making electrical connection with a conductor in an insulated cable.
A variety of arrangements for making electric contact or connection with conductors in an insulated cable are known. Cables which are installed as internal bus cable systems in vehicles are being used to an ever-increasing extent, particularly in automobiles. In addition, it has been found expedient to use so-called ring circuits, which are installed in a vehicle when it is manufactured. The ring circuits are continuous circuits having, as a rule, no initial contact interfaces. This is because automobiles are ordered by customers with varied equipment rather than identical equipment and some electrical components are installed after they are ordered. As a result, the automobile equipment bus circuit is universally installed initially as a ring circuit. During manufacture of a vehicle more or fewer individually locatable electrical connection devices are required at suitable positions within the vehicle depending upon equipment features in order to connect, for example, electric window openers or other equipment-dependent electrical components directly, to the ring circuit. The provision of a ring circuit with direct electrical connection arrangements eliminates the need for cable harnesses, at least in certain sections within the vehicle. In addition, this procedure not only has manufacturing advantages, but advantages that appear in later use of the vehicle as well. For example, if in the later use of a vehicle a conventional cable harness having an electrical component breaks down, a large number of cables have to be found and followed in order to find a possible contact problem. In a bus ring circuit, only the contact element that connects to the particular defective component has to be found in order to be able to follow and possibly find a faulty mechanical contact or determine whether the component to which it is connected is defective.
The starting point in the use of such a bus ring circuit is the connection of the corresponding electrical component to the bus circuit, i.e., establishment of the contact.
In this connection, German Offenlegungsschrift No. 30 30 286 discloses an electrical connection plug in which a plurality of insulated wires are engaged by cutting elements. In this case, the cutting elements, which constitute electrical contacts, engage the wires in such a way that the insulation is pierced and the cutting elements either contact the conductors or, for better contact, possibly even cut partially into the conductors. Thus, the cutting elements form the electrical contacts that produce an electrical connection between the corresponding individual wire conductors and a cable connector or the like which is inserted into the plug.
When bus circuits are used in motor vehicles, they must also withstand rough everyday operation. This means exposure in some cases to varying thermal loads in a temperature range near the engine from about minus 40 degrees to up to 100 degrees Celsius, for example. It is known that, with varying temperature loading, environmental influences due to moisture or corrosive substances act especially rapidly and strongly affect the connection thus established by permanent corrosion. In automobile manufacture, however, it is required that secure connection under these environmental influences must be assured for at least 15 years.
Under these conditions, it is insufficient merely to enclose such a connection.
Other prior art, for example German Offenlegungsschrift No. 44 27 675, discloses an electrical connector which is sealed with a gel. In this arrangement, a cable end or a plug is introduced into a plug-in device and sealed with gel by a pressing or tamping device. The embodiment described in that document is disadvantageous because the device as a whole is complicated and is not useful for a ring circuit since it requires a separate electrical wiring arrangement consisting of two circuit sections which, moreover, provides for only one cable.
In addition, European Published Application No. 0 731 531 discloses an electrical connector in which a cable conductor mounted on a sleeve can be slipped onto a plug contact which receives the sleeve. That arrangement has a gel reservoir within the sleeve which is located so that, when the cable is inserted, the gel reservoir is first pierced and thereafter, i.e., when the cable is pushed in further, electrical contact is made with a contacting lug. Subsequently, pressure is exerted on the gel reservoir by a tamping device so that the gel is distributed within the plug. This is disadvantageous because, upon introduction of the cable, the gel reservoir is first pierced so that the cable conductor becomes coated with the gel and electrical contact is made only after the cable conductor has been coated, which may lead to a faulty connection. In this case, too, the device cannot be used for a connection of a ring circuit, since the wiring arrangement requires two separate circuit sections to be connected together.